Exercise device



FIG. 1 is a side elevation view of an exercise device showing my new design;

FIG. 2 is a plan view of the design shown in FIG. 1;

FIG. 3 is a bottom plan view of the design shown in FIG. 1;

FIG. 4 is a rear view of the design shown in FIG. 1; and,

FIG. 5 is a front view of the design shown in FIG. 1. 

An ornamental design for an exercise device, substantially as shown and described. 